Roof support assemblies



May 3, 1966 D. H. H. BOLTON ETAL 3,248,885

ROOF SUPPORT ASSEMBLIES 2 Sheets-Sheet 1 Filed Oct. '7, 1963 \NvEN-roRS MIL/MEL 'Po'77'sv- BY PWGLAS MH- 7301.73 M M A'r'roRNEYS ROOF SUPPORT AS SEMBLIES 2 Sheets-Sheet 2 Filed Oct. '7, 1963 Imam-0R M afi/AEL c. ToTTs 4' BY DbuLAS $01-$11 A'TTQRNEY:

Patented May 3, 1966 3,248,885 RQOF SUPPORT ASSEMBLIES Douglas H. H. Bolton, Winchcombe, near Cheltenham, and Michael C. Potts, Prestbury, (Iheltenham, England, assignors to Dowty Mining Equipment Limited, a British company Filed Oct. 7, 1963, Ser. No. 314,304 Claims priority, application Great Britain, Oct. 10, 1962,

4 Claims. (Cl. 61-45) This invention relates to roof support assemblies suitable for use in mines.

The present invention provides a roof support assembly including a series of advanceable roof supports and a Series of warning devices located adjacent to and associated with the roof supports in such a manner that each warning device operates to give a warning when a roof support in its vicinity is about to advance. Thus, when the roof supports are advanced in sequence, the position of a warning device emitting a warning indicates the position that the advancing sequence has reached. Each warning device may be operable by an operation that precedes an advancing operation of a roof support in its vicinity. Thereby a workman in the vicinity is warned that an advance is about to occur, and that the roof in that vicinity is not fully supported, for support is at least partially withdrawn during an advance. v r

The warning emitted by each warning device may be audible and each warning device is preferably mechanically operable.

Each warning device may be operated by a change in length of a fluid-pressure-operated jack member associated with a roof support in the vicinity of the Warning device. The jack member may be loosely mounted in a sleeve member, one such member being secured to the roof support and the other member being secured to an advanceable anchorage, and one of the members may carry a warning device operated by movement of the jack member within the sleeve member.

The sleeve member may carry the warning device which includes a projection lying in the path of a portion of the jack member, said portion having a projection which engages the projection of the warning device, as the jack member moves within the sleeve member, to cause the warning device to operate.

" One embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings of which,

FIG. 1 is a diagrammatic view of mining apparatus, with the hydraulic connections and roof bars omitted.

FIG. 2 is a similar view on a larger scale of part of the mining apparatus showing the hydraulic connections.

FIG. 3 is a sectional view of one of the conveyoradvancing jack assemblies, and

FIG. 4 is a sectional view of the conveyor-advancing jack assembly taken along the line 4-4 of FIG. 3, some parts being omitted.

With reference to the accompanying drawings, known coal mining apparatus includes a conveyor 1 which extends along the working face 2 of a coal mine and acts as a guide means for a coal cutting machine 3 in addition to conveying coal cut by the cutting machine 3. A series of hydraulically-operated roof supports 4 are arranged along the working face 2 and lie on the opposite side of the conveyor 1 to the working face 2.

Each roof support 4.includes a ground-engaging sole beam 5 which carries a number, for example three as shown, of hydraulically-operable telescopic props 6 and a roof-engageable bar (not shown) carried by the props 6. Each roof support 4 has a single-acting hydraulicallyoperable jack 7 mounted in the sole beam 5, the piston rod of the jack being secured to the conveyor 1 by a chain 8, or by any other means. This jack 7 is used to advance the roof support 4 towards the conveyor 1 with the conveyor 1 acting asan anchorage. The chain S-reduces the risk of any damage such as bending of the jack 7 which would be caused if the jack 7 was secured directly to theconveyor 1 and creep of the conveyor 1 relative to the roof supports 6 occured, conveyor creep being movement of the body of the conveyor 1 along the working face 2.

Some roof supports 4 (for example every fourth roof support as shown).have a double-acting hydraulicallyoperable jack 9 for advancing the conveyor 1 relative to the roof support 4 using the roof support 4 as an anchorage. The cylinder of the jack 9 is pivotally secured to a lug 11 projecting from the side of the sole beam 5, and is a loose fit within a sleeve 12 pivotally secured to the conveyor 1. When advancing the conveyor 1, the piston rod 13 of the jack 9 acts against the end of the sleeve 12 adjacent the conveyor 1. When the roof support 4 is to be advanced, the jack 9 is first contracted and the loose fit of the jack '9 in the sleeve 12 ensures that no side loads are applied to the roof support 4 by the jack 9 during the advance of the roof support 4. It is'during this contraction, preferably, that the signal is given, with which this invention is concerned.

A hydraulic power unit 14 is-located at one end of the working face 2 and a main pressure line 15 and a hydraulic return line 16 extend from a source 17 of hydraulic pressure in the power unit 14 along the working face 2. Each roof support 4 includes a hydraulic control valve 18 to which the pressure line 15 and return line 16 are connected by lines 19 and 21 respectively. The control valve 18 of each roof support 4 is connected to its props 6, jack 7 and jack 9 (if provided). The control valve 18 of each roof support 4 provided with a jack 9 may be so arranged that the jack 9 is urging the conveyor 1 towards the working face 2 continually except when the roof support 4 is being advanced. I If desired, however, the control valve 18 of each roof support 4 provided with a jack '9 may be operable to cause the jack 9 to urge the conveyor 1 towards the working face 2 only when desired. For example, the control valve 18 may be manually operable, operable by a remote control, or operable by a device travelling with the cutting machine 3 to cause the jack 9 to urge the conveyor 1 towards the working face 2.

Actuation of each control valve 18 to cause its roof support 4 to undergo an advancing operation is caused by a hydraulic pilot system. T he power unit 14 includes a source 22 of hydraulic pressure for the pilot system, and a pilot line 23 extends from the pilot source 22 and passes through the control valve 18 of each roof support in turn. Each control valve 18 initially closes the pilot line 23. When the pilot source 22 is operated to pressu-rise the pilot line 23, the hydraulic pressure in the pilot line 23 acts as a signal to the control valve'18 of the first roof support 4, which then undergoes an advancing operation in the following manner:

i (a) The jack 9 (if provided) is caused to cease pushing the conveyor 1 forwardly, and is itself contracted,

(b) The props 6 are contracted to release the roof support 4 from the roof,

(c) The jack 7 is caused to advance the roof support 4 up to the conveyor 1 and, Y

(d) After support advance has been completed, the jack 7 is caused to cease urging the roof support 4 forwardly, and the props 6 are extended to reset the roof support 4 against the roof. The jack 9 may then resume pushing the conveyor forwardly.

When the roof support 4 has been satisfactorily reset against the roof, the satisfactory resetting being sensed by the attainment of a desired hydraulic pressure in the props 6, the control valve 18 of the first roof support is caused J to open the pilot line 23 so that the hydraulic pressure signal is then applied to the control valve 18 of the next roof support 4, which then undergoes an advancing operation. Thus each roof support 4 in turn undergoes an advancing operation.

The hydraulic operation of the mining apparatus so far described is more fully described in United States patent application Serial No. 282,760, filed May 23, 1963, and United States patent application Serial No. 314,132, filed October 7, 1963.

In accordance with this invention, a series of warning devices are provided. In this embodiment, each conveyor advancing jack assembly, that is to say, each jack as sembly that includes a jack 9, has a warning device. FIGS. 3 and 4 show in detail the conveyor-advancing jack assembly which includes the jack 9 and the sleeve 12.

The jack 9 includes a double-walled cylinder 25 formed by two radially-spaced tubular members 26, 27 closed at one end by an end member 28. The end member 28 carries a lug 29 by means of which the jack 9 is pivotally secured to the lug 11 of its roof support 4. The piston rod 13 carries a piston 31 sealingly engaging the inner wall of the tubular member 27 of the cylinder 25, and the piston rod 13 passes through an end member 32 of the cylinder 25 so as to project from the cylinder 9.

To extend the jack 9, fluid under pressure is passed into the cylinder 25 through a conduit 33 in the end member 28, effecting movement of piston rod 13 to the left, as viewed in FIGURE 3, and to contract the jack 9, fluid under pressure is passed into the cylinder 25 through an aperture 34 in the tubular member 26, through the space between the tubular members 26 and 27 and through an aperture 35 in the tubular member 27.

The sleeve 12 has an end member 36 which carries two lugs 37 by means of which the sleeve 12 is pivotally secured to the conveyor 1. The warning device includes a pillar 67 secured to the outside of the sleeve 12, the

pillar 67 carrying a bell member 38. A shaft 39 is carried by two lugs 41 secured to the outside of the sleeve 12, and the shaft 39 carries a projection 42 which projects into the space within the sleeve 12. The shaft 39 carries an arm 43 to which is secured a resilient striker arm 44 carrying a striker 45. The arm 43 is resiliently biased to the position shown in FIG. 3 by the combined action of springs 46 and 47. Spring 46 acts between the arm 43 and a hell cover 48 which is secured to the outside of the sleeve 12. Sprinl 47 surrounds the shaft 39 and acts between the projection 42 and a cover plate 49 secured to the lugs 41.

The end portion of the piston rod 13 projecting from the cylinder 25 and into the-interior of sleeve 12 carries a sleeve 51 which has a number of axially-spaced circumferential projections 52 (four, as shown) positioned so as to successively engage the projection 42 as the end portion of the piston rod 13 moves past the projection 42.

The position shown in FIG. 3 of the various parts of the conveyor-advancing jack assembly occurs when the roof support 4 has been fully advanced up to the conveyor 1. When the conveyor 1 is to be advanced, the jack 9 is extended by fluid under pressure, and hence the piston rod 13 moves towards, and then engages the end member 36, before advancing the conveyor 1. As the piston rod moves towards the end member 36, the projections 52 successively engage the projection 42 and move the shaft 39 in a clockwise direction. Consequently, the striker 45 is moved into engagement with the adjacent portion of the bell member 38 and any subsequent movement of "the projection 42 and arm 43 causes resilient bending of the striker arm 44. This movement of the piston rod 13 to jack 9, the piston rod 13 is abutting the end member 36.

Therefore, as the piston rod 13 is withdrawn into the cylinder 25 to contract the jack 9, and before advance of the roof support by the jack 7 begins, the projections '52 successively engage the projection 42 and move the shaft 39 in an anti-clockwise direction, thus moving the striker 45 away' from the adjacent portion of the bellmember 38. When each projection 52 leaves the projection 42, the spring 46 causes the striker 45 to hit the bell member 38 with sufficient force to cause a loud bell-like sound to be emitted. As four projections 52 are shown, the contraction of the jack 9 causes four bell-like sounds to be emitted. These four sounds are therefore emitted immediately before the roof support 4 advances.

Thus in this mining apparatus an audible warning is given immediately before the advance of each roof support 4 equipped with a conveyor advancing jack 9, each warning emanating from a position in the vicinity of the roof support which is to advance.

We claim as our invention:

1. A roof support assembly including an advanceable roof support, an advanceable anchorage, a fluid-pressureoperated jack member operable by extension to advance the anchorage relative to the roof support, and a sleeve member in which the jack member is slidably mounted, one such member being-secured to the anchorage and the other member being secured to the roof support, one of the members carrying an audible warning device and the other member carrying an actuator for said warning device in position to engage the same upon contraction of the jack member within the sleeve member.

2. A roof support assembly according to claim 1, wherein the sleeve member carries the warning device, the warning device including a projection lying in the path of a portion of the jack member, and such portion of the jack member being arranged to engage the projection of the warning device, as the jack member contracts within the sleeve member, thereby to operate the warning device.

3. A roof support assembly according to claim 2, wherein the warning device includes a bell and a resiliently mounted striker, the projection being carried by the striker,

.and upon engagement by said portion of the jack' member retracting and then releasing the striker, to strike the bell and produce an audible signal.

4. A roof support assembly according to claim 3, wherein the striker-engaging portion of the jack member includes an extension formed with a series of circumferential projections spaced in the direction in which the jack member contracts.

References Cited by the Examiner UNITED STATES PATENTS 9/1914 Wales 91-1 FOREIGN PATENTS 882,210 11/1961 Great Britain. 882,947 11/1961 Great Britain.

CHARLES E. OCONNELL, Primary Examiner. JACOB SHAPIRO, Examiner. 

1. A ROOF SUPPORT ASSEMBLY INCLUDING AN ADVANCEABLE ROOF SUPPORT, AN ADVANCEABLE ANCHORAGE, A FLUID-PRESSUREOPERATED JACK MEMBER OPERABLE BY EXTENSION TO ADVANCE THE ANCHORAGE RELATIVE TO THE ROOF SUPPORT, AND A SLEEVE MEMBER IN WHICH THE JACK MEMBER IS SLIDABLY MOUNTED ONE SUCH MEMBER BEING SECURED TO THE ANCHORAGE AND THE OTHER MEMBER BEING SECURED TO THE ROOF SUPPORT, ONE OF THE MEMBERS CARRYING AN AUDIBLE WARNING DEVICE AND THE OTHER MEMBER CARRYING AN ACTUATOR FOR SAID WARNING DEVICE IN POSITION TO ENGAGE THE SAME UPON CONTRACTION OF THE JACK MEMBER WITHIN THE SLEEVE MEMBER. 